Diesel engine exhaust purifier

ABSTRACT

A diesel engine exhaust purifier includes a burner system having a metal barrel mounted in the exhaust pipe of a diesel vehicle and a flame thrower mounted in the metal barrel, pressure sensors mounted in the front and rear ends of the metal barrel, a precious metal catalyzer converter type filter system mounted in the metal barrel for removing solid matters from engine exhaust gas and a microcontroller electrically connected to the power supply system of the diesel vehicle for driving the pump-operated fuel tank of the flame thrower to deliver forced fuel out of a fuel nozzle and an auto igniter to ignite the mist of fuel discharged out of the fuel nozzle for burning out cumulated carbon subject to the detection of the pressure sensors.

BACKGROUND OF THE INVENTION

(a) Technical Field of the Invention

The present invention relates to a carbon deposition eliminationtechnology and more particularly, to a diesel engine exhaust purifierthat effectively eliminates cumulated carbon from the exhaust pipe of adiesel vehicle.

(b) Description of the Prior Art

A diesel vehicle uses compression ignition to burn fuel oil orsubstitute fuel, performing the diesel cycle to convert chemical energyinto thermal energy and power output. During combustion, pollutantsincluding PM (particulate matter), smoke, NO_(x) (mono-nitrogen oxides),CO (carbon monoxide), SO_(x) (sodium oxides), CO₂ (carbon dioxide), HC(hydrocarbon) and other waste matters are produced and discharged out ofthe exhaust pipe into the atmosphere, causing damage to the ozone layer,occurrence of acidic rain and rise in greenhouse effect. In case PM(particulate matter) in exhausted waste gas contain polycyclic aromatichydrocarbons or metal oxides, breathing in such exhausted waste gas maycause lung, bronchi or breathing passage diseases. According to a localair pollution source investigation, 46% of particulate matter and 51% ofNO_(x) of mobile source of air pollution came from diesel vehicles. Mostbig public transportation vehicles are of diesel vehicles. To controldischarge of diesel engine waste gas is an important measure to improveair quality.

The automotive industry has been continuously proposing new measures toreduce the exhaust amount of waste gas. One of the best ways to reducethe exhaust amount of waste gas from the diesel engine of a dieselvehicle is to install an exhaust gas purifier in the exhaust pipe.However, carbon will deposit in the filter element of the exhaust gaspurifier to block the passage after a long period of work, therebyaffecting exhausting effect and normal functioning of the diesel engine.

When a certain amount of carbon is cumulated in the filter element ofthe exhaust gas purifier of the exhaust pipe of a diesel vehicle, thepassage of the exhaust gas purifier will be partially blocked, causing arise in pressure (back pressure) in the exhaust pipe. Therefore, abackpressure sensor may be installed in the exhaust pipe of a dieselengine to detect the pressure level of the waste gas in the filterelement of the exhaust gas purifier, monitoring the status of depositionof carbon. When the deposition of carbon in the inside wall of theexhaust pipe reaches a certain thickness, the backpressure sensor willdetect a high level of back pressure, and the engine management systemwill give a signal to increase the working temperature of the dieselengine, thereby burning out cumulated carbon. However, when a vehiclestops frequently due to a poor traffic condition or frequently runs atidle speed due to driver's personal driving habit, the low engine speedcannot raise the engine working temperature for enabling the cumulatedcarbon to be burned out. When an excessive amount of carbon is cumulatedin the exhaust gas purifier of the exhaust pipe, the driver may have tosend the vehicle to an auto repair and service center, asking a mechanicto clean the exhaust pipe and to remove deposition of carbon from theexhaust gas purifier. This manner is inconvenience and time-wasting.

To meet new vehicle exhaust emission standards, electronic directignition system may be used with a nested ceramic filter element tofiltrate carbon dioxide, hydrocarbon, mono-nitrogen oxides, sodiumoxides and black ash particles. When the back pressure surpasses apredetermined value, diesel oil is added to the engine valve outlet toincrease the combustion temperature, or added to the inside of theexhaust pipe near the filter element to increase the temperature of thefilter element, causing cumulated carbon in the filter elements to beburned out. However, installation of the electronic direct ignitionsystem and the nested ceramic filter element in an existing dieselvehicle is complicated. A modification of the original electronicstructure of the diesel vehicle is necessary. This modificationcomplicates further maintenance of the diesel vehicle.

Therefore, it is desirable to provide a diesel engine exhaust purifierthat eliminates the aforesaid problems.

SUMMARY OF THE INVENTION

The primary purpose of the present invention is to provide a dieselengine exhaust purifier, which eliminates the drawback of conventionaldiesel engine exhaust purifiers that cause the working temperature ofthe diesel engine unable to be effectively increased due to utilizationof the working temperature of the engine for burning cumulated carbon.

It is another object of the present invention to provide a diesel engineexhaust purifier, which fits any of a variety of existing dieselvehicles without any modification of the electronic structure of thediesel vehicle, saving much the installation cost and facilitatingvehicle maintenance.

Technically, the invention has a burner system and a filter systemconnected in series and installed in the exhaust pipe of a dieselvehicle. When a certain amount of carbon is cumulated in the exhaustpipe, the back pressure will be relatively increased. When the backpressure surpasses a predetermined value, a microcontroller drives anindicator light to flash and enables engine exhaust gas to be directlydischarged into a combustion chamber in a burner system for burning atabout 400° C., so that cumulated carbon is completely burned out within20 minutes, cleaning the filter system in the rear side of the exhaustpipe.

The filter system uses precious metal ceramic filter elements to removesolid matters from exhaust gas. The precious metal ceramic filterelements are prepared from magnesium oxide, aluminum oxide, siliconoxide or the like through a sintering process, having 100 meshes persquare inch. Each mesh has one end opened and the other end closed.Thus, exhaust gas cannot pass through the meshes directly and must movealong the wall of the exhaust gas passage. The porosity is about 7˜13μ.Therefore, about 99% of black ash particles can be caught. The preciousmetal ceramic filter elements have a precious metal coating (platinum,palladium, rhodium or titanium coating) that oxidizes toxic gas orcauses toxic gas to be converted into nontoxic gas for exhaust. Thefilter system eliminates 90% and up HC (hydrocarbon) and CO (carbonmonoxide), and 20% up NOx (mono-nitrogen oxides) from exhaust gas.

According to the technical features of the present invention, the burnersystem is installed in the exhaust pipe in front of the filter systemand adjacent to the exhaust port of the diesel engine. The burner systemcomprises a stainless steel barrel, and a flame thrower connected to amiddle part of the stainless steel barrel. The flame thrower iscontrolled by a microcontroller. When the working time of the dieselengine surpasses 50 hours (this is adjustable subject to the type of thediesel vehicle) or when the back pressure reaches 6 kpa, a correspondingindication signal is produced, and the driver can directly switch on thecontrol button to turn on the igniter of the burner system and then toturn on the motor pump of the pump-operated fuel tank of the burnersystem. If the temperature rise does not reach 20° C. within 60 seconds,ignition is started again. If burning is not initiated twice, failureindicator light is turned on. At this time, a troubleshooting isnecessary. When fuel sensor means detected fuel low, the burner systemis turned off. The burner system is started again when a new supply offuel is added. The burning process is completed when the set burningtime period of 20 minutes is up. Thus, cumulated carbon is effectivelyeliminated.

The foregoing object and summary provide only a brief introduction tothe present invention. To fully appreciate these and other objects ofthe present invention as well as the invention itself, all of which willbecome apparent to those skilled in the art, the following detaileddescription of the invention and the claims should be read inconjunction with the accompanying drawings. Throughout the specificationand drawings identical reference numerals refer to identical or similarparts.

Many other advantages and features of the present invention will becomemanifest to those versed in the art upon making reference to thedetailed description and the accompanying sheets of drawings in which apreferred structural embodiment incorporating the principles of thepresent invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plain view of a diesel engine exhaust purifier inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions are of exemplary embodiments only, and arenot intended to limit the scope, applicability or configuration of theinvention in any way. Rather, the following description provides aconvenient illustration for implementing exemplary embodiments of theinvention. Various changes to the described embodiments may be made inthe function and arrangement of the elements described without departingfrom the scope of the invention as set forth in the appended claims.

Referring to FIG. 1, a diesel engine exhaust purifier for use in adiesel vehicle in accordance with the present invention comprises aburner system 13 and a filter system 7 arranged in an exhaust pipe 1between an input end 11 and an output end 12 of the exhaust pipe 1. Theburner system 13 comprises a stainless steel barrel 24, a flame thrower2 mounted in the stainless steel barrel 24, and an auto igniter 3. Theflame thrower 2 comprises a pump-operated fuel tank 23, a nozzle 21, anda fuel pipe 22 connected between the pump-operated fuel tank 23 and thefuel nozzle 21 for guiding fuel from the pump-operated fuel tank 23 tothe fuel nozzle 21 that sprays fuel into a mist. The auto igniter 3 isdisposed adjacent to the fuel nozzle 21, and electrically connected tothe DC power supply circuit of the diesel vehicle. When electricallyconnected, the auto igniter 3 discharges sparks to burn the mist of fuelbeing discharged out of the fuel nozzle 21. A first pressure sensor 5Ais disposed in front of the flame thrower 2 and adapted to detect backpressure. The first pressure sensor 5A is mounted in one sidewall of theburner system 13 at a suitable location and electrically connected tothe control system of the diesel vehicle. According to the presentpreferred embodiment, the first pressure sensor 5A is electricallyconnected with the pump-operated fuel tank 23 to a microcontroller 4.The filter system 7 is a precious metal catalyzer converter installed inthe output end 12 of the exhaust pipe 1, comprising a straight throughprecious metal catalyzer type ceramic filter element 71 and a nestedmetal catalyzer type ceramic filter element 72. A temperature sensor 6is installed in one side of the filter system 7. A second pressuresensor 5B is installed in the output end 12 of the exhaust pipe 1. Thetemperature sensor 6 and the second pressure sensor 5B are electricallyconnected to the microcontroller 4.

The burner system 13 of the exhaust pipe purifier does no work under anormal working status of the diesel vehicle, and exhaust gas of thediesel engine is directly discharged through the burner system 13 andthe filter system 7. When exhaust gas is flowing through the filtersystem 7, the straight through precious metal catalyzer type ceramicfilter element 71 and the nested metal catalyzer type ceramic filterelement 72 remove solid matters from exhaust gas. When gas discharge issmooth, the back pressure detected by the first pressure sensor 5A isunder a predetermined value, at this time, the flame thrower 2 is notstarted. If a certain amount of carbon is cumulated in the filter system7 after a long use, the exhaust back pressure will be increased. Whenthe back pressure detected by the second pressure sensor 5B surpassesthe predetermined value, the second pressure sensor 5B provides a signalto the microcontroller 4, causing the microcontroller 4 to start up thepump (not shown) of the pump-operated fuel tank 23. Thus, thepump-operated fuel tank 23 supplies forced fuel through the fuel pipe 22to the fuel nozzle 21 for burning. At the same time, the microcontroller4 drives the igniter 3 to discharge sparks, causing the mist of fuelbeing discharged out of the fuel nozzle 21 to be burned. When thedischarging mist of fuel is burned, the temperature will be as high asabout 400° C. This high temperature is transferred to the straightthrough precious metal catalyzer type ceramic filter element 71 and thenested metal catalyzer type ceramic filter element 72 of the filtersystem 7, causing cumulated carbon to be burned out. After removal ofcumulated carbon, the filter system 7 resumes to function smoothly. Atthis time, the back pressure detected by the first pressure sensor 5Adropped below the predetermined value, and the first pressure sensor 5Agives a signal to the microcontroller 4 to turn off the flame thrower 2,allowing engine exhaust gas to be directly discharged through the filtersystem 7. This operation procedure is repeated again and again,effectively eliminating cumulated carbon.

It will be understood that each of the elements described above, or twoor more together may also find a useful application in other types ofmethods differing from the type described above.

While certain novel features of this invention have been shown anddescribed and are pointed out in the annexed claim, it is not intendedto be limited to the details above, since it will be understood thatvarious omissions, modifications, substitutions and changes in the formsand details of the device illustrated and in its operation can be madeby those skilled in the art without departing in any way from the spiritof the present invention.

1. An exhaust pipe purifier installed in the exhaust pipe of a dieselvehicle to eliminate cumulated carbon from the exhaust pipe, comprising:a burner system, said burner system comprising a metal barrel mounted insaid exhaust pipe, a flame thrower mounted in said metal barrel, saidflame thrower comprising a pump-operated fuel tank, a fuel nozzleadapted to spray a fuel into a mist, a fuel pipe adapted to guide a fuelfrom said pump-operated fuel tank to said fuel nozzle for spraying intoa mist, and an auto igniter adapted to discharge sparks for burning themist of fuel discharged out of said fuel nozzle, a first pressure sensormounted in said metal barrel near a front end thereof; a second pressuresensor mounted in said metal barrel near a rear end thereof; a filtersystem mounted in said metal barrel between said burner system and saidsecond pressure sensor and adapted to remove solid matters from engineexhaust gas; and a microcontroller electrically connected to the powersupply system of the diesel vehicle and electrically connected to saidfirst pressure sensor and said second pressure sensor and said burnersystem and adapted to control the operation of said pump-operated fueltank and said auto igniter subject to pressure detection of said firstpressure sensor and said second pressure sensor.
 2. The exhaust pipepurifier as claimed in claim 1, wherein said filter system comprises astraight through precious metal catalyzer type ceramic filter elementand a nested precious metal catalyzer type ceramic filter connected inseries.